Process of reducing the consistency of



States. Patcut rn'o'cass .OFREDUCING THE CONSISTENCY F SOLIEAND-LIQUID MIXTURES,

laiu1smricri u pnlic i6n Germany ep mb '1, "1 5.4.

" (chasei ThisJinvention relates to a process for reducing the consistency ofsolid-and-liquid mixtures, which is fapplie cable to various industrial purposes in which it is desired eitherhto reduce the consistency. of such mixture 'for a given solids content'or toincrease the solids content of a solid-andrliquid mixture. withthesame. or even reduced final consistency. l

.Jhe. possibility of increasing the fiuidityof a. thick or pasty-suspension or. 'of increasing its .solids. content and specific gravity.lwithout obtaining an inadmi'ssibly thick suspension is of special importance in the heavy-media separation .of. minerals, such as ore. and coal- Aqueous suspensions of finely ground heavy solids, as a rule of ferrosilicon, magnetite, ga 1ena,pyrite, quartz, bariunrsulphate, 'or'the-like, are used for preparing the heavy 'mediuminwhich-the separation is efiected in said classifying processes- V 'j lieavy inediamade-with these substances have the disadvantage, -however, -that'their consistency (apparent viscosity "increasesprogressively with 'an increase in their content -of-heavy solids,'i.'e. with an increase in gravity, so thatthe specific gravity of heavy media having-a consistency whichds compatible with a perfect float andsink process cannot be in'creased in practice beyond approximately. half the specific gravity of the heavy solid used because otherwise the. lighter. particles of theymaterial-to be classified will noglonger float since in most mineral mixtures to be subjected to heavy-media separation the difierence between the specific gravities of the components to be separated is not too great. For this reason'it has previously been necessary to use heavy solids of very high specific gravity.

, The resulting difficulties and disadvantages are removed according to the invention thereby that small quantities of certain interface-active substances are added to the he u p a elee s ha ei e of h sclid a e es us ed in he l uid is n r a ed y te ai e c ive substancesadded."

. This efi otthje newprocess may be decisive tor-its application evenwhere'the reductionfof the consistency is not c ica Interface:active substances suitable for the purpose. of the invention'include cationiecompounds of the series Consisting-of. the fattymines and their salts, preferably a y am nes. ,QnHsni HQ n t e r a t CnH2n+1NH3C (chl r de) a d nH2nd-1 H3 C 3 c t tQ)a 91 as stcarylamine C H N I Q, stearylamine acetate C H NH OOCCH and stearylamine hydrochloride C H NH Cl or coconut amine, tallow amine and their salts. .In, the. formulae given the indexnstates. the

1 afimbe of b n 'a bms f-t e mole u e; th p6 s en aboutoand 18. carbon atoms, between 6and ,1 8. which said substances are added, are The. optimum quantities can concerned have. bet in theol qdl ls.

he proportions in' m sm l i a ses.

be ieasily detei mined. Ciaenerally they are between rote yskun is red a media, whereby the consistency of the suspensions is reduced in such a degree that a considerable increase in the volume share of the heavy solid is possible, e.g., in making a heavy medium for classification purposes. In many cases this enables also the preparation of suspensions having the specific gravity required for the separation while using comparatively light-weight heavy solids. For instance, it is now possible to use as heavy media suspensions whose heavy solids consist of one or several heavy components of the mineral mixture to be classified. A suspension of barium sulphate can be used, e.g., for separating a mixture of barium sulphate and quartz. According to the new process the consistency of said mixture is in spite of its high content of solids reduced far enough to ensure a perfect separation with reference to the specific gravity.

Another advantage of the invention resides in the fact that in most cases the addition of the surface-active agents will considerably increase the stability of the suspension compared to one that has not been treated according to the invention. This is due to the fact that l20.kg./n1, depending on the activity of the particular substance added,'

' ereduc 'on of. consistency'of the. heavy medium as enabl'efd bytheinv tion does. not onl'yincrefase. the

1 precision'of separat hllt' alsofth h q l l l 33 g ined' materialdown, idea. 1 mm; ven thefi est part's oi.the heavy sickly in the.

.9 quickly on of the dilute suspension obtained by sprinkling onthe w hing screens because its particles tend to fioc owing to the" addition of the. interface active agents, when the suspension has been dilutedto. a critical point, which is below the "concentration used for the sink float process. "Another'applicationof the new process is found iii h kjhis d s men where q artieanataials:are

' wet-ground. The addition oftheinterface-active agents enables a---considerablereduction of the water content of the mix obtained bygrinding, without impairing its p mn bi u hu the h awea m o in t e s sequenttherrnail tr ent of thefgiround material inthe In this connection the simultaneous stabilizing efiect tthe, d itiv s. .aeeordinato the invention is of advau t g gth 'g'r ndifi oper t on, b ca e it, caus s, theeqa p rticle ,0 qu ckly, hat hey r subjected th Q whereasth fines in suspension?" In the subsequent examples the results achieved wi the application of the new process to the sink-float separation are compared with those obtained with the previously usual procedure.

Example 1 During the conventional sink-float classification of a Ruhr lean coal having a particle size of 1-5 mm. in a barium sulphate suspension having a specific gravity of 1.9 (specific gravity of barium sulphate=3.88, grain size 100% below 0.06 mm.) the yield of float was 60.5%, misyield (related to l00%)=8.74. The yield of sink was 39.5%, misyield (related to l00%)=31.13%.

When 4.5-5.5 kg./m. of coconut amine acetate were added to the heavy medium to reduce its consistency, the quality of the separation was enhanced as follows: Yield of float misyield (related to %)=0%. Yield of sink 35%, misyield (related to 100% =6.99%,'

The sink-float classification of the same Ruhr coal of a smaller particle size of 0.5-1 mm. in the same barium sulphatesuspension without addition of consistency reducing agent resulted in a yield of float of 58.20%, misyield (related to 100%)=17.55, and a. yield of sink of 41.80%, misyield (related to 100%):1-57.10%. After an addition of. 4.5-5.5 kg./m. of coconut amine acetate to the barium sulphate suspension the following results were obtained: Yield of float 63.50%, misyield (related to 100%)=0%; yield of sink 36.50%, misyield (related to 100%)=4.27%. In the aforegoing examples the term misyield is employed to indicate that portion of the material treated which is not true sink or float material and is considered as a loss unless recycled.

Example 3 ries which are suitable for the float and sink separation and have a high specific gravity, containing more than 50% by volume of heavy solids, for'the classification of ore.

A slurry made with an eutectic lead-tin alloy having a specific gravity of 8.11 as'a heavy solid had ca. 9.0 kg./m. of coconut amine acetate added thereto. This enabled an increase of the heavy-solids content of the slurry to 56% by volume, resulting in aslurry having a specific gravity of 5.02, without impairing the usefulness of the suspension for the separation.

That slurry was used for classifying Kiruna magnetite into low-phosphorus and high-phosphorus components.

Initially that magnetite floated entirely in the suspension having the specific gravity 5.02. After a small reduction of the specific gravity only the high-phosphoru component of the ore floated.

Numerically the result was as follows:

Percent Yield 013- by Percent Percent Weight Fe P Fe P Example 4 The solids did not settle out appreciably from this thin slurry within 30 seconds.

After 8.5-9.0 kg./m. coconut amine acetate was added the thin slurry had clarified almost completely after 30 seconds as a result of the flocculation.

The foregoing examples of applications for the new process in various fields could be amplified as desired in the sense of the general statements hereinbefore.

What is claimed is:

1. In a sink-float separation process in which'an aqueous suspension of a heavy solid is employed as a heavy medium for such separation, the step which comprises incorporating an alkyl amino compound selected'from the group consisting of alkyl amines of the formula C H NH in which n is an integer between 6 and 18 and their salts in the aqueous suspension of the heavy solid employed for such separation medium to reduce the apparent viscosity thereof, the quantity of heavy solid in said suspension being so high that in the absence of said amino compound its. apparent viscosity would betoo great for use as a sink-float separation medium.

2. The process of claim 1 in which the quantity of alkyl amino compound incorporated in the suspension is from 1 to 20 kg. per cubic meter of suspension.

3. The process of claim 1 in which a mixture of such alkyl amino compounds is incorporated in the suspension.

4. The process of claim 1 inwhich said alkyl amino compound is a coconut amino compound.

References Cited in the file of this patent UNITED STATES PATENTS 2,108,495 Levin Feb. 15, 1938 2,286,835 Robinson et al June 16, 1942 2,309,931 Cameron Feb. 2, 1943 2,320,009 Ralston et al. May 25, 1943 2,331,049 Schindler Oct. 5, 1943 2,468,657 Dyke et al. Apr. 26, 1949 2,568,992 Doscher Sept. 25, 1951 2,589,949 Meadors Mar. 18, 1952 2,599,342 Meadors June 3, 1952 ,719,010 Erickson Sept. 27, 1955 FOREIGN PATENTS 830,341 France May 9, 1938 532,103 Great Britain Jan. 17, 1941 OTHER REFERENCES A Armeens: Bookiet pub. by Armour Chem. Div.,

Armour and Co., Chicago, Ill., August 1949, 6 pp.

McCray: Chemistry and Control of Lime Base Muds, article in The Petroleum Engineer, November 1949, pp.

B-54, B-56 and B-58. 

1. IN A SINK-FLOAT SEPARATION PROCESS IN WHICH AN AQUEOUS SUSPENSION OF A HEAVY SOLID IS EMPLOYED AS A HEAVY MEDIUM FOR SUCH A SEPERATION, THE STEP WHICH COMPRISE INCORPORATING AN ALKYL AMINO COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKYL AMINES OF THE FORMULA CNH2N+1NH2, IN WHICH N IS AN INTEGER BETWEEN 6 AND 18 AND THEIR SALTS IN THE AQUEOUS SUSPENSION OF THE HEAVY SOLID EMPLOYED FOR SUCH SEPERATION MEDIUM TO REDUCE THE APPARENT VISCOSITY THEREOF, THE QUANITY OF HEAVY SOLID IN SUCH SUSPENSION BEING SO HIGH THAT IN THE ABSENCE OF SAID AMINO COMPOUND ITS APPARENT VISCOSITY WOULD BE TOO GREAT FOR USE AS A SINK-FLOAT SEPERATION MEDIUM. 